A number of extremely active promutagens, originally obtained by pyrolysis of amino acids, have been found also in pyrolysates of various plant and animal proteinaceous materials (soybean globulin, casein, gluten, and albumin), in cigarette smoke condensates, and in broiled or fried fish or beef. We will develop methodologies for measuring the content of these promutagens in food and in biological fluids and tissues. In addition, we will synthesize two of the most potent promutagens in the group that have been previously isolated from pyrolysates of tryptophan and glutamic acid, incorporating 14C into a metabolically stable position. These will be used in model experiments on the metabolic disposition of these compounds in rats. In other studies, we will use primary rat hepatocyte cultures to investigate the mechanism of the metabolic activation of these promutagens to mutagens. By combining research groups expert in synthetic and structural organic chemistry with others expert in microbial genetics and in biochemical pharmacology, we expect to establish a base of knowledge regarding the disposition and the mechanism of action of these compounds in the rat. In addition, the rat studies will provide a testing ground for methodologies for detecting ultramicro amounts of the compounds and their metabolites in excreta. Finally, we expect to use these methodologies to assess the presence of these compounds in food and excreta of human subjects under strict dietary control, thus providing a first assessment of the potential risk that these compounds present to man.